npx create-react-app test-countdown --template=typescript
yarn add antd

// App.tsx
/* eslint-disable @typescript-eslint/no-useless-constructor */
import React from 'react';
import { Tooltip, Modal, Button } from "antd";
import './App.css';
// 秒轉(zhuǎn)時間
function convertSecondsToHMS(seconds: number) {
  const hours = Math.floor(seconds / 3600);
  const minutes = Math.floor((seconds % 3600) / 60);
  const remainingSeconds =  Math.floor(seconds % 60);
  const formattedTime = `${hours}小時 ${minutes}分鐘 ${remainingSeconds}秒`;
  return formattedTime;
}
// 倒計時組件props格式
type IProps = {
  level: boolean;
  timeRemain: number;
}
// 倒計時組件state格式
type IState = {
  level: boolean;
  timeRemain: number;
  lastMountedTime: number;
  timeCountdown: number;
  timer: any;
}
// 倒計時組件
class App extends React.PureComponent<IProps, IState> {
  state = {
    lastMountedTime: 0,
    timeRemain: 0,
    timeCountdown: 9999,
    level: false,
    timer: null,
  }
  // 多余的構造函數(shù)
  constructor(props: IProps) {
    super(props);
  }
  // 組件構建完畢之后需要將props中設置的等級,倒計時存到state中去
  // 此外還需要將當?shù)貢r間存到state中去作為之后計算的參考
  // 最后開啟定時器,并將定時器的handle存到state中去
  componentDidMount(): void {
    const { timeRemain, level } = this.props;
    const lastMountedTime = +new Date();
    const timer = setInterval(
      () => {
        this.setState(()=>({
          timeCountdown: this.state.timeRemain - (+new Date() - this.state.lastMountedTime) / 1000,
        }))
      }, 200
    )
    this.setState({
      lastMountedTime,
      timeRemain,
      level,
      timer,
    })
  }
  // 在組件卸載之前需要釋放定時器
  componentWillUnmount(): void {
    if(this.state.timer) clearInterval(this.state.timer);
  }
  // 如果用戶是VIP則tooltip上不顯示訪問剩余時間
  // 如果用戶是訪客,則字體變成紅色,tooltip顯示倒計時
  // 如果倒計時為0則彈出模態(tài)框通知用戶試用結(jié)束
  render() {
    const info = this.state.level ? 'VIP用戶' : '訪客模式';
    const fontColor = this.state.level ? 'black' : 'red';
    const timeCountdown = this.state.timeCountdown > 0 ? this.state.timeCountdown : 0;
    const toolTipInfo = this.state.level ? '' : convertSecondsToHMS(timeCountdown);
    return (
      <div className="App">
        {
          timeCountdown > 0 ? (
            <Tooltip
              title={toolTipInfo}
              placement="top"
            >
              <span
                style={{
                  color: fontColor
                }}
              >{info}</span>
            </Tooltip>
          ) : (
            <Modal
              open={true}
              destroyOnClose={true}
              getContainer={() => document.body}
              onCancel={() => { window.location.replace('') }}
              closable={true}
              maskClosable={true}
              title={`授權到期`}
              footer={[
                <Button size="small" onClick={() => { window.location.replace('') }}>
                  取消
                </Button>,
              ]}
              width={215}
              bodyStyle={{
                padding: 0
              }}
            >
              <div>
                您的訪客模式到期了
              </div>
            </Modal>
          )
        }
      </div>
    )
  }
}
export default App;

// index.tsx
root.render(
    <App timeRemain={5300} level={false}/>
);
// 這里去掉了嚴格模式